Multinationals are bracing for sweeping changes to the way countries tax them and gather data as Canada and other developed countries join in a global corporate tax crackdown.
The Organization for Economic Co-operation and Development is busily drafting a set of common global standards for taxing multinationals, slated to be rolled out starting in September.
"This is happening. We are on track," Pascal Saint-Amans, the OECD's director of tax policy administration told an industry briefing last week.
The update from OECD officials follows the recent release of a series of controversial discussion papers, laying out what the new standards will look like.
The changes are aimed at blocking companies from exploiting gaps in international rules to avoid taxes and to better capture the digital economy and improve transparency. Among other things, the new rules would require better disclosure of what companies pay in taxes, their banking information and how much revenue they generate around the world.
They would also curb the use of loopholes, the shifting of profits to low-tax countries and hybrid tax schemes designed to take advantage of special tax breaks.
Countries suspect they may be losing out on billions of dollars a year in corporate taxes.
The ability of companies such as Apple Inc. and Amazon.com Inc. to duck taxes has become a lightning rod for cash-strapped governments, still paying down debts run up during the financial crisis.
The changes amount to the most significant overhaul of global rules in decades, according to tax experts.
"It's a very significant change going on," said Michael Peggs, who runs the transfer pricing practice at Cadesky & Associates LLP in Toronto.
"This isn't tinkering. These are sea changes in international tax [rules]."
But he said companies don't know when and how far countries will go to implement the OECD's recommendations.
"There is a lot of angst in the tax community and among companies about what's going on," Mr. Peggs said. "They are dealing with a very ambitious timeline. This is a very fast-tracked modernization."
Jodi Kelleher, national leader of the international tax practice at KPMG in Canada, said companies are nervously watching the process.
"Clearly, there is a lot that could come up that would impact Canadians," she said.
In its last budget, the federal government announced it was seeking comments on a rule that would thwart so-called "treaty shopping," by using shell company affiliates in low-tax countries.
Albert Baker, a partner and tax policy leader at Deloitte in Toronto, said the new standards are "very broad and very intrusive."
He pointed out that while most countries agree that enhanced disclosure is needed, there is still considerable debate about many other measures.
Britain, for example, recently introduced a so-called "patent box" system that allows companies to pay lower taxes if they develop and keep intellectual property in the country. Countries without such breaks see it as a way for multinationals to avoid taxes.
He said getting the changes could be easy in some countries, but much more difficult in countries such as the U.S., where Congress is deadlocked on many key issues.
"There is a high level of uncertainty because we don't know what will happen," Mr. Baker said.
Companies almost certainly will have to reorganize how they structure their businesses once the new regime is in place, he added.
Adding to the uncertainty, the tax crackdown is being driven by the Group of 20 countries, which includes some non-OECD members, including China, Brazil and India.
Canada is a member of both groups.